Tension device



Nov. 19, 1963 R G. COKER ETAL TENSION DEVICE 3 Sheets-Sheet 1 Filed June 19, 1961 PREssuRE SOURCE- Nov. 19, 1963 R. G. coKER ETAL 3,111,285

TENSION DEVICE Filed June 19, 1961 3 Sheets-Sheet 2 INVENTOR5 F 4 Ram-mam G.COKE-R and EDGAR E. ROWE CHARLES K. buNLAmJE.

ATTORNEY Nov. 19, 1963 R. G. COKER ETAL TENSION DEVICE 3 Sheets-Sheet 5 Filed June 19, 1961 INVENTORS RICHAED G. COKEEand EDGAR 12. Rowe- CHARLES K.

%N LAFSIE.

ATTORNEY United States Patent 3,111,285 TENSEGH Richard G. Jo ner, Edgar Rowe, and Qhiules Burriap, 5n, Hartsviile, $.11, assignors to Eonoeo lroducts Qornpany, Hartsvilie, Sil, a corporation of South Qarolina Filed .lune 19, 1233, Ser. No. M7,??? 2 (Ilaims. oi. ass-75.2

This invention relates to a tension device and more particulmly to a device for producing a predetermined tension in advancing sheet material such as a paper strip.

Many operations in use today utilizing sheet material in strip or ribbon-like form require that the advancing sheet material be maintained at a selected tension for proper utilization of the material. Sue such operation in common use today involves the use of a plurality of strips of paper or similar in terial which are simultaneously unwound from supply rolls and wrapped onto a mandrel for forming into a spirally wound, multi-ply paper tube. it is very important in a spiral tube winding operation that the tension in the paper strips being advanced to the spiral tube making machine be maintained at a selected tension so that the tube winding operation can be properly performed and a spiral tube of the proper construction be produced.

Many tension devices have been proposed for producing tension in such advancing paper strips which, while producing tension in the strips, are characterized by other drawbacks which make them undesirable for use in a pr0- duction installation. Presently employed tension devices re characterized by such limitations as poor resistance to Wear by the paper, difiiculty or inability of the devices to produce a tension within precise limits on the paper strip and to maintain a preset tension.

One of the most undesirable features of presently employed tension devices, in particular, tension devices which frictionally engage the paper strip surfaces, results from the inability of such devices to handle paper strips which contain randomly distributed irregularities in the paper thickness. These irregularities are generally caused by the inclusion within the strip of foreign matter, trash, and other particles common to the less expensive types of paper employed for such end uses as the making of spiral tubes. When paper having such surface irregularities or thickened areas passes through the tension device, an increase in the frictional forces applied by the tension device occurs in these areas generally resulting in a tearing of the paper. The tube Winding operation must then be stopped and the torn or severed paper strip spliced with an attendant expenditure of time and labor adding considerably to the manufacturing costs.

Accordingly, a primary object of this invention is to provide a new and novel tension device for sheet material.

Another object or" this invention is to provide a new and novel tension device for producing tension in an advancing paper strip of the type utilized in a spiral tube winding operation.

A further object or" this invention is to provide a new and novel tension devic for sheet material such as a paper strip which permits the production of a uniform, emily controlled tension in the paper strip and which permits irregularities such as thickened portions in the paper strip to pass readily through the tension device without tearing.

till another object of the invention is to provide a new and novel tension device for sheet material such as a paper strip which is simple in construction, which is readily adjustable for producing a selected tension in the sheet material over a wide range and which may be conveniently installed in groups for maintaining a uniform 2 tension in a plurality of paper strips with regulation and adjustment of the tension from a central source.

Other obiects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings.

in general, the objects of the invention and related obiects are accomplished by providing tension means including a suitably supported back-up member and friction means associated with said back-up member. Sheet material is advanced between the back-up member and the friction means and means are provided for yieldingly urging the friction means into frictional engagement with the advancing sheet material against the back-up member to produce a predetermined tension in the advancing sheet material. The friction means comprises independently yielding portions each of which yield independently without interruption in the tension producing engagement of all of the portions with the sheet material to permit sheet material portions of increased thickness to pass thereunder and th refore avoid tearing of the sheet material.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is an isometric view of a group of tension devices constructed in accordance with the invention arranged in an operating position;

FlGURE 2 is an isometric view of the embodiment of the invention shown in FlGURE 1;

FIGURE 3 is a sectional view taken substantially along line 3-3 of FEGURE 2 in the direction of the arrows;

FEGURE 4 is a sectional view taken substantially along line of FIGURE 2 in the direction of the arrows;

FIGURE 5 is an isometric view similar to FlGURE 2 of another embodiment of the invention;

FIGURE 6 is a sectional view taken substantially along line 6i of FIGURE 5 in the direction of arrows;

7 is a sectional view taken substantially along line 7-7 of FEGURE 5 in the direction of the arrows; and

FEGURE 8 is an end view of the tension device of HGURE 5.

Referring now to the dr wings and to FIGURES 1, 2 in particular, there is shown in FIGURE 1 a plurality of tension devices constructed in accordance with the invention and arranged for operation as a group. The embodiment of the invention shown in FIGURES 1, 2 is generally referred to by the numeral 11. It will be noted that the tension devices 11 shown in FEGURE 1 are utilized to control the tension in sheet material such as paper strips l2 arranged in a vertically spaced manner such as is well known in the manufacturing of spirally wound, multi-ply paper tubes utilizing paper strips simultaneously unwound from supply rolls (not shown). However, it should be understood that the tension devices 11 of the invention may be used to control tension in any type of sheet material utilized in any suitable operation Within the scope of the invention.

The tension devices 11 are arranged in a vertically spaced relationship in the particular arrangement illustrated and are supported on an upstanding post 13 by means of slidable clamps 1-4 arranged to be secured in a selected vertical position by means of a screw 15. Each tension device 11 is connected by means of a rod 16 suitably clamped by means such as a screw 17 t0 the clamping member 14.

In the embodiment of FIGURES 1 through 4, the tension device 11 comprises end plates 21, 22 having openings 23, 24 respectively therein. The end plates 21, 22. are suitably secured by means such as welding or the like to opposite ends of substantially semi-circular nested split tubes 26, 27 as shown best in FIGURES 3, 4. As shown, the radius of the split tube 27 is selected to permit the nesting of tube'2'7 within tube 26 and the wall of tube 27 is extended so as to provide edge portions 27a, 2722 which extend upwardly from the side edges of the split tube 26. A back-up member or rod 23 is also provided in the tension device 13 which rod is preferably inserted through suitable openings 29, 3% in the end plates 21, 22 respectively.

An expansible tubular member 31 comprising a tube of resilient material such as rubber or the like is positioned within the inner split sube 27 with its terminal ends received within the central openings 23, 24 in the end plates 21, 22. The ends of the tube 31 are fixidly held within the plates 21, 2 2 by means of plugs 32, 33 having central openings 3 35 respectively. It should be understood that the plugs 32,, 33 together with portions of the tube 31 are preferably press fitted into the ends plates openings 34', 35 to securely retain the ends of the rubber tube 31. One end of the support rod 16 is positioned witl1 in the opening 34- in the end plug 32 for mounting the tension device 11.

As shown in FIGURE 1, a suitable source of air pressure communicated with the interior 36 of the rubber tube 31 by means of a pressure regulating valve 37, a pressure gauge 33, a flexible hose 39 and an on-ofi valve it positioned within a line ii communicating with the tube interior 36 by means of a fitting inserted Within the central opening 35 in the end plug 33. t will be noted in FIGURE 1, that a single pressure regulating valve 37 and pressure gauge 38 are provided for central uniform control of the plurality of tension devices '11 through a plurality of hoses 3'9 connected thereto.

Friction means are provided in the tension device 11 for frictionally engaging a paper strip 12 which in the embodiment of FIGURES 1 through 4 comprise a row of arcuate segments 46 arranged in side-by-side relationship. The segments 46 are positioned over the upper surface of the rubber tube 31 and float thereon being retained guidably for movement upwardly by the edge portions 27a, 27b of split tube 27. The segments 46 are arranged to be moved upwardly into frictional engagement with a paper strip 12 against the back-up rod 28 as the paper strip is advanced between the segments and the rod.

in the operation of tension device of FZGURES 1 through 4, the paper strip 12 is advanced in the direction of arrow 1 between the row of segments 1-6 and the rod 23 as shown. The on-otf valve 40 is opened to communicate the interior 36 of the rubber tube 31 with the source of air pressure so that the rubber tube interior 36 is pressurized and the tube expands upwardly as shown in FIG- URE 4 to yieldingly urge the arcuate segments 46 against the surface of the strip 12 against the rod 28. The pressure within the tube interior 35 is preset by means of the regulating valve 37 so that the desired amount of tension is produced in the paper strip 12 in accordance with the pressure exerted by the segments 46 on the strip surface.

As shown best in FIGURE 3 when a surface irregularity such as a portion of increased thickness appears in the surface of the paper strip 3.2 which thickened portion or lump has been identified by the numeral 51 in ETGURE 3, the floating segment as lying thereunder is moved radially inward as shown as permitted by the yielding action of the rubber tube 31 against the pressure within the tube interior 36. The frictional forces exerted on the advancing strip 12 and consequently the tension produced by the tension device ii is not interrupted as all of the segments 46 continue to be yieldingly urged into engagement with the strip. Thus, tearing of the paper strip is avoided which would otherwise occur by an unrelieved abnormal 4 tension which would occur at the particular spot in the paper strip identified by the lump 51.

Referring now to FIGURES 5 through 8 there is shown another embodiment of the tension device of the invention which is designated generally by the numeral 61. In general, the tension device 61 is supported in a manner similar to the tension device i of FIGURE 1 on a support rod 62 as shown in FlGURE 5. However, in the embodiment of EEGURES 5 through 8, the rod 62 extends through the tension device 61 to serve as a back-up member corresponding to the rod 2?: of the embodiment of FIGURES 1 through 4.

End plates ea, 64 are provided which are positioned in spaced relationship on the rod 62 by means of openings 66, 67 in plates 63, 64 respectively through which the rod extends. Any suitable means such as welding may be used for securing the plates 63, as in position on the rod 62. The plates 63, as are also provided with openings 63, 69 respectively for receiving a rock shaft 71 secured against axial movement by means such as annular washers 72 suitably positioned as shown on the shaft.

As in the previous embodiment, friction means are provided on the tension device 61 which comprise a plate 73 suitably secured along one edge by means such as welding or the like to the rock shaft 71. The plate 73 is prov ed with a plurality of parallel slits 74 extending throu out the major portion of the plate from the plate forward edge to an area 73a on the plate 73 adjacent the rock shaft 71. These slits 74 provide a row of fingers 76 which are sufficiently flexible to flex yieldingly out of the normal planar form of the plate bending about a base defined by plate area 730.

of the fingers 76 have attached to their forward or outer end a wear resistant member such as a rod portion 77 of hardened steel or the like. These rod portions 77 are thus arranged to frictionally engage the advancing paper strip '12 moving the strip against a hardened insert 73 suitably positioned within a longitudinally extending slot 79 formed in the underlying surface of the rod 62 as shown.

Means are provided for yieldingly urging the plate 73 and thus all of the fingers 76 into frictional engagement with the paper strip 12 to produce a predetermined tension in the paper strip. More specifically, a crank arm 63 is suitably attached by means such as a set screw 82 to one end of the rock shaft 71 and is arranged to be engaged by the forward end of a piston 83 reciprocally movable within a fiuid pressure cylinder 84 of any conventional type.

The fluid pressure cylinder 84 is connected to a suitable source of fluid pressure such as compressed air by means of a line 96 through an on-olf valve 97 in a manner similar to the embodiment of FIGURES 1 through 4 to provide for movement of the piston 33 within the cylinder 84.

The fluid pressure cylinder 84 is suitably positioned on an L-shaped bracket 91 which is mounted by means of screws 92, 93 on the end plate 64 as shown. A slot 94 is provided in the bracket H as shown in FIGURE 8 through which the lower screw 93 passes which permits the bracket and consequently the cylinder 84 to be pivoted throughout a limited range to predetermine the point on the crank arm 81 engaged by the forward end of the piston 83. in this manner, the effective length of the lever arm of crank arm 31 can be preset thereby permitting adjustment of the pivoting force applied to the plate 7 3.

In the operation of the embodiment of FIGURES 5 through 8, the paper strip 12 is advanced in the direction of the arrow H between the rod 62 and the friction plate 73 as shown clearly in FIGURE 7. The plate 73 is pivoted in the direction of the arrow P (FIGURE 5) by actuation of the pressure cylinder 84 through the source of compressed air to engage the forward end of the piston 83 with the crank arm till after an adjustment has been made in the angular position of the cylinder 34 by means of the slot 94 and screw 3.

The rotation of the rock shaft 71 resulting from the force exerted on the crank arm 81 by the piston 83 pivots the plate 73 and engages the forward ends of all f the fingers 76 by means of the rod portions 77 attached thereto with the upper surface of the paper strip 12 against the insert 78 in the rod 62 as shown best in FIGURE 7. The pressure supplied to the cylinder 84 through the pressurized air line 96 and the point of contact of the piston forward end 83 with the crank arm 81 determine the force with which the rod portions 77 engage the paper strip 12 and consequently the tension which is developed within the advancing paper strip 12.

As in the previous embodiment, each of the fingers 76 are arranged to yield in the presence of an irregularity in the paper strip 12 such as a portion of increased thickness passing thereunder. This action is shown clearly in FEGURE 6 where a portion of increased thickness or lump 98 is shown passing beneath one of the fingers 76 and the rod portion 77 attached thereto so that this finger 76 is lifted or moved yieldingly upward to permit the lump 98 to pass without tearing of the paper strip. At the same time, uniform tension is maintained throughout the paper strip 12 as there is no interruption in the urging force applied to all of the fingers 76 by the pivoting of the rock shaft 71 and the plate 73 attached thereto. It should be understood that the embodiment of FIGURES 5-8 may be employed in multiple and controlled from a central pressure source as in the embodiment of FEGURES 1-4.

It can be seen that with the novel construction of this invention, a tension device has been provided which is simple, compact and inexpensive in construction and which produces a tension in advancing paper strips which can be controlled accurately at any selected level within a wide range. The tension device of the invention is particularly suitable for use in a spiral tube winding operation wherein a plurality of paper strips are used, all of which strips must be maintained at a predetermined tension, as the compact nature of the tension device permits an arrangement of a plurality of these devices within a relatively small space for gang operation. The objectionable features of presently employed tension devices have been eliminated with the tension device of the invention and, in particular, tearing of the paper strips resulting from sharp increases in localized friction during the passage of thickened portions in the paper strip common to presently employed devices has been eliminated. The tension device of the invention lends itself to many forms within the scope of the invention, two of which have been disclosed.

While there has been described what at present is considered to be the preferred embodiment of the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Having thus described the invention, what is claimed is:

l. A tension device for advancing sheet material comprising, in combinaiton, a back-up member, a row of floating arcuate segments associated with said back-up member, means for guidably supporting all of said segments for unrestrained vertical movement upwardly into frictional engagement with said advancing sheet material against said back-up member, unitary means operatively associated with all of said segments for yieldingly uinging all of said segments into said frictional engagement with said sheet material to produce a predetermined tension in said sheet material, each of said floating segments movable independently against said urging means to permit sheet material portions of increased thickness to pass thereover without tearing of said advancing sheet material and without interruption in the tension producing engagement of all of said segments with said sheet material.

2. A tension device for advancing sheet material comprising, in combination, an elongated support member, a back-up member associated with said support member, a row of floating arcuate segments guidably supported on said support member in alignment with said iback-u-p member, an expansible hollow member positioned on said support member in engagement with all of said segments, a source of fluid pressure, means connecting said source of fluid pressure with the interior of said hollow member for expanding said hollow member and yieldingly urging all of said segments into frictional engagement with sheet material advancing between said back-up member and said segments to produce a predetermined tension in said sheet material, each of said floating segments movable independently against said expansible tubular member to permit sheet material portions of increased thickness to pass thereover without tearing of said advancing sheet material and without interruption in the tension producing engagement of all of said segments with said sheet material.

References Cited in the file of this patent UNITED STATES PATENTS 926,508 Paterson June 29, 1909 1,297,809 Dixon et al Mar. 18, 1919 1,469,728 Levy Oct. 2, 1923 2,899,199 Stobb Aug. 11, 1959 2,930,270 Brey Mar. 29, 1960 

1. A TENSION DEVICE FOR ADVANCING SHEET MATERIAL COMPRISING, IN COMBINATION, A BACK-UP MEMBER, A ROW OF FLOATING ARCUATE SEGMENTS ASSOCIATED WITH SAID BACK-UP MEMBER, MEANS FOR GUIDABLY SUPPORTING ALL OF SAID SEGMENTS FOR UNRESTRAINED VERTICAL MOVEMENT UPWARDLY INTO FRICTIONAL ENGAGEMENT WITH SAID ADVANCING SHEET MATERIAL AGAINST SAID BACK-UP MEMBER, UNITARY MEANS OPERATIVELY ASSOCIATED WITH ALL OF SAID SEGMENTS FOR YIELDINGLY URGING ALL OF SAID SEGMENTS INTO SAID FRICTIONAL ENGAGEMENT WITH SAID SHEET MATERIAL TO PRODUCE A PREDETERMINED TENSION IN SAID SHEET MATERIAL, EACH OF SAID FLOATING SEGMENTS MOVABLE INDEPENDENTLY AGAINST SAID URGING MEANS TO PER- 